Refactor `NDS` and `DSi` to be objects (#1893)

* First crack at refactoring NDS and DSi into objects

- Remove all global/`static` variables in `NDS` and related classes
- Rely more on virtual dispatch when we need to pick methods at runtime
- Pass `NDS&` or `DSi&` to its constituent components where necessary
- Introduce some headers or move some definitions to break `#include` cycles

* Refactor the frontend to accommodate the core's changes

* Move up `SchedList`'s declaration

- Move it to before the components are initialized so the `map`s inside are initialized
- Fields in C++ are initialized in the order they're declared

* Fix a crash when allocating memory

* Fix JIT-free builds

* Fix GDB-free builds

* Fix Linux builds

- Explicitly qualify some member types in NDS, since they share the same name as their classes

* Remove an unnecessary template argument

- This was causing the build to fail on macOS

* Fix ARM and Android builds

* Rename `Constants.h` to `MemConstants.h`

* Add `NDS::IsRunning()`

* Use an `#include` guard instead of `#pragma once`

1 files changed, 3 insertions, 1 deletions

diff --git a/src/DSi_AES.h b/src/DSi_AES.h
index 9c0a63f..4df8269 100644
--- a/src/DSi_AES.h
+++ b/src/DSi_AES.h
@@ -45,10 +45,11 @@ __attribute((always_inline)) static void Bswap128(void* Dst, const void* Src)
 #endif
 #pragma GCC diagnostic pop
 
+class DSi;
 class DSi_AES
 {
 public:
-    DSi_AES();
+    DSi_AES(melonDS::DSi& dsi);
     ~DSi_AES();
     void Reset();
     void DoSavestate(Savestate* file);
@@ -73,6 +74,7 @@ public:
     static void DeriveNormalKey(u8* keyX, u8* keyY, u8* normalkey);
 
 private:
+    melonDS::DSi& DSi;
     u32 Cnt;
 
     u32 BlkCnt;